Whining/Droning Noise from Triangle Tube Boiler

Kynes1000

We have a persistent whining/droning noise coming from our 18-month old triangle tube boiler (we moved into the house 6 months ago so inherited it).  The whining noise occurs when the radiant floors or radiators call for heat.

The boiler powers 3x radiant floor zones (tekmar thermostats) and 2x radiators.  It also heats the indirect domestic hot water storage tanks.

The hot water tanks don’t seem to cause the noise.  However, if any of the radiant or radiator zones call for heat the noise starts.  It’s driving me crazy.  Noise can be clearly heard inside and even louder from the exterior exhaust pipe.  I am in Chicago and have had a few people out to look but no success.

Any thoughts or suggestions would be appreciated!  

kcopp

Which model? Sounds like it could be a fan issue.

Derheatmeister

Only at low fire for the radiant?
Did they do a combustion analysis ?

Kynes1000

The boiler model is a Triangle Tube Instinct Solo Wall 110. Had the original installer out who said no fan issue he could see.

Low fire - I am not sure the answer to this question as don't know my way around a boiler/radiant well enough... How would I figure that out?

Combustion Analysis - They did NOT run a combustion analysis. Original boiler installer informed me they had run a combustion analysis at install. They could do it again. I had mentioned to him that the exterior exhaust smelled like gas more than I thought it should. He checked it out and it didn't smell strong to him but, again, mentioned they could run the combustion test.

Derheatmeister

Low fire is when boiler is modulating on the bottom end..
I would start with a combustion test in low then high fire as per manufacturers instructions
Adjustment should be done during this time..
The before and after test values of this should be printed out and left on site..

Ironman

If a combustion analysis and proper adjustments toward the richer end of the manufacturer’s chart doesn’t fix it, then CSST used in the gas line is the likely culprit.

https://forum.heatinghelp.com/discussion/164856/csst-the-cause-of-harmonic-fog-horn-noise#latest

Kynes1000

Thank you - that makes sense.  I will have them do a combustion analysis.

Interestingly enough, it was near zero degrees in Chicago yesterday and I only heard the boiler make the noise once.  I’m guessing maybe it was in high fire given the cold temp.  So, maybe it is only happening in low fire.  

Kynes1000

just wanted to update that adjusting towards richer end fixed the harmonic noise. We ended up getting on the phone with triangle tube support as there were some more detailed/complicated adjustments that could be made (I don't understand all of it) and that did the trick. Thanks to everyone for the input and thoughtful answers!

GGross

@Kynes1000

Out of curiosity is this set up with LP or natural gas?

Kynes1000

Natural gas

Tim_D

Improper combustion set up, CSST gas piping and/or undersized gas piping can all cause unwanted harmonics.

Kynes1000

The issue with my droning, 2-year old Triangle Tube boiler has re-appeared. It was fixed for a bit but then the screen went out, they replaced the screen and it started up again. At this point I have replaced the fan, gas valve, and computer screen (under warranty) and it's still making the noise. No CSST is being used. It has to be the combustion setup, right? The contractor has run a couple of combustion analysis tests but I have not seen a printout of the results. Last time contractor came they determined it had to be the gas valve since, replaced it but still didn't fix the job. I'm left wondering what to do next... Would appreciate any ideas you guys have. Thanks!

Kynes1000

also - I should mention that the droning only occurs in low fire, when the radiators/radiant floors call for heat. In high fire, when the indirect domestic water tank calls for the boiler, there is no noise.

Alan (California Radiant) Forbes

Another call to tech. support with your contractor on site is indicated. This is getting pretty granular and only someone very familiar with your boiler model can help. Good luck and let us know what happens. 

You just might need a new circuit board. 

Teemok

I had a bad experience tuning one of these "Instinct" 155 boilers. There are two gas valve adjustments, just like many other designs. There's the offset (careful fine experienced adjustment only) and the throttle for rich/lean. I have correctly set up many boilers and water heaters that were very maladjusted over the years. I'm not green. I would set this problem Instinct up spot on and then find it faulting out on failed ignition. Tech Sup. wanted me to raise the min. firing rate. Nope, that's not the fix. I replaced the igniter and did a full disassembly inspection of the gas train and burner. After exhausting every possible gas supply problem, I zero-ed in on this tuning change/drift over time. Of course my new gas analyzer was interrogated a few times. Finally I set it up on the very rich end of spec. and it settled in to a the middle of range. Something in the gas valve linkages I guess. The very short flue was a suspect but was not an issue. The serial number was very low so I chalked it up to an early production fault. I stared to request a warranty gas valve but since that last adjustment it's has been great. It is in a mission critical-heavy use application. It was very frustrating dealing with it involving many no heat lock outs and business interruptions. My resolve was tested and my customer nearly forced a swap. Mine would run for a week or two before locking out. All the signs of running too lean a mix where there, including a very dirty igniter. That dirty igniter is also the flame sensor probe and that's is why it locked out. It couldn't sense the flame anymore. The noise you previously corrected by a using a richer tuning is very often a mixture/combustion related resonance thing. The offset tuning is tested by comparing low fire and high fire gas analyzer test numbers. Low fire should be about 0.1% leaner/lower for a Co2 reading than the high fire reading. If the difference is much larger than that or richer at low fire you need an experienced tech to help set it up correctly. If the offset is good, I recommend going with a more rich initial tune and you may also find it leans out over some time.

GGross

Teemok said:

I had a bad experience tuning one of these "Instinct" 155 boilers. There are two gas valve adjustments, just like many other designs. There's the offset (careful fine experienced adjustment only) and the throttle for rich/lean. I have correctly set up many boilers and water heaters that were very maladjusted over the years. I'm not green. I would set this problem Instinct up spot on and then find it faulting out on failed ignition. Tech Sup. wanted me to raise the min. firing rate. Nope, that's not the fix. I replaced the igniter and did a full disassembly inspection of the gas train and burner. After exhausting every possible gas supply problem, I zero-ed in on this tuning change/drift over time. Of course my new gas analyzer was interrogated a few times. Finally I set it up on the very rich end of spec. and it settled in to a the middle of range. Something in the gas valve linkages I guess. The very short flue was a suspect but was not an issue. The serial number was very low so I chalked it up to an early production fault. I stared to request a warranty gas valve but since that last adjustment it's has been great. It is in a mission critical-heavy use application. It was very frustrating dealing with it involving many no heat lock outs and business interruptions. My resolve was tested and my customer nearly forced a swap. Mine would run for a week or two before locking out. All the signs of running too lean a mix where there, including a very dirty igniter. That dirty igniter is also the flame sensor probe and that's is why it locked out. It couldn't sense the flame anymore. The noise you previously corrected by a using a richer tuning is very often a mixture/combustion related resonance thing. The offset tuning is tested by comparing low fire and high fire gas analyzer test numbers. Low fire should be about 0.1% leaner/lower for a Co2 reading than the high fire reading. If the difference is much larger than that or richer at low fire you need an experienced tech to help set it up correctly. If the offset is good, I recommend going with a more rich initial tune and you may also find it leans out over some time.

were yours LP or natural gas? You should not ever need to open the adjustment on the instinct for proper tuning on Nat gas. However when tuning for LP there was a requirement to do so, the change you would note over time is likely due to not waiting long enough between the very slight adjustments made to the adjustment screw (not the brass throttle screw which will not change over time) I have personally taken apart the instinct gas valves, they are not special really, that adjustment screw is pushing against a little diaphragm that will control the mixture, you have to give it a solid 2-3 minutes between each VERY slight adjustment made to ensure the tuning is accurate and the diaphragm has properly moved to the adjustment you made. The throttle screw is just spinning a "cat's-eye" shaped piece of plastic on the inlet of the gas valve, this part can't move over time, there isn't a way for that to happen, it can also spin round-and-round so you can't really overdo that one, if you get lost you can take the gas valve out and watch as you turn the "cat's eye" to get it back to center to start over.

In addition to all of this, the very first series of instinct had a programming issue on LP gas, they would NOT tune in to proper combustion, short vents were also an issue with these units for some reason. Local reps were tasked with going to the field and re-commissioning the affected LP units once the official change was cemented. I spent many many hours in the field tuning these for contractors when they first came out, there was one that was nearly vibrating off the wall (Vent caused this) and another that did the same thing (yet again the vent) All of these issues disappeared after the LP update was done at the factory level.

Teemok

It is a natural unit. After 3 lock out events, I spent hours. Testing, letting it run, ramping it up and down and testing it again, then again the next day. It was changing. I'd come back to lean mixes after carefully biasing to rich. Yes I know to wait for a good reading after an adjustment. Out of the box the offset was off. There is a diaphragm reacting to the throttle position. That is what I thought could settle or seat after adjustment but you may know better. Early on I added 2-90's to the flue but it changed nothing. All is well that ends well. I opened it up after a year and it was nice and clean. The Igniter looked normal.
It heats a high BTU load hot yoga studio to 120F with a large custom made fan coil fitted inside an old roof top Reznor furnace casing, 10-14 hours a day, 7 days a week 2-10v control. Very glad it works well. It was my custom hydronic solution for a very difficult design problem and customers. I didn't charge enough to deal with that kind of pressure or extended responsibility. I'm wiser and could replicate it with ease but I don't see that ever happening. I knew some of that early Instinct history. I extracted it from the TT tech support guys. Thanks for sharing your info and helping.

Kynes1000

Had another service call on the triangle tube boiler today.  Performed a combustion analysis and tested low fire three times and it would not hold the right level so…They are diagnosing it as ANOTHER bad gas valve.  I just replaced the gas valve 5 months ago and it’s bad again?!? Something is wrong here and I’m wondering if I just have a lemon of a boiler.  Has anyone ever seen this before?  Triangle tube is trying to tell me I’m out of warranty now.  It’s insane

pedmec

If your having trouble at low fire you need to adjust the Bias screw. Did they bother adjusting the Bias screw?

Kynes1000

On a prior visit they had adjusted some screws but I’m not sure if it was the specific one you mentioned.  On this occasion, and the previous occasion, they were on the phone with triangle tube tech support and the conclusion was faulty gas valve since it wouldn’t hold the same combustion reading once set.  Would the Bias screw impact that?

Teemok

Has the total equivalent pipe length of the flue and intake piping been checked? Also flue termination orientations. Re-breathing exhaust is a common problem or water trapping in horizontal piping. If the flue and intake piping is too long you just can't maintain proper air flow on low fire, regardless of a rich enough mixture tune. If the flue is within the max. length spec. and the correct size for your set up, first suspect is tuning and then air flow restrictions in (piping, burner (sheet rock dust), HX, fan problem/ fouling) would be my next checks. In the installers settings there is a minimum firing rate that can be set higher as a band aid. I think there's an ignition fan speed setting as well. Someone who knows how to tune this boiler well should reset bias. Band aiding a bad tune isn't good. There is a curve the bias setting screw changes and it's very sensitive. You can get good Co2 numbers on either side of that curve but only one side is correct and it will have in spec. CO (carbon monoxide) readings as well as in spec Co2. I think the ideal is spot on the peak of the curve but we tend to fault to one side. The side of the curve to bias on makes low fire just a bit richer (0.1 % Co2 higher) than on high fire. The process is tedious and dependent on good procedure as well as a well zeroed out and un-fouled Co capable combustion meter. For whatever reasons I found setting the bias correctly and then setting the throttle on the richer side made it settle in to perfect tune. The factory procedure is good (For my setup 1/10 th of a turn on the bias screw is a large adjustment. Go with 1/20th adjustments when you're close and wait for results on the meter. Recheck by ramping up to high fire, look for in spec numbers and then go to low again to find the same numbers as before.
https://cdn.triangletube.com/wp-content/uploads/2021/12/21205002/EB073-Instinct-Gas-Valve-Adjusment.pdf

Big Ed_4

Make sure the plastic air horn is still attached to the fan ..

Kynes1000

Thank you.  Piping, fan, and burner are all confirmed good so we’ve ruled that out.

Combustion analysis on last visit calibrated the gas control 3 times and every time they cycled the firing rate from 1% to 100% and back the gas control failed to hold calibration in low fire.  As a result, Triangle tube support is saying it has to be a bad gas valve despite replacement of the valve five months ago.  Could it be the circuit board?  Feels like something is just wrong with the system…

they did the band aid you suggested and set min firing rate to 25% so that the boiler only makes the noise when it start up until it gets over 25%.  It helps since it doesn’t make the noise once it hits 25% but still howls for 10-15 seconds as it’s ramping up.

I’ll ask about the bias screw - thanks for the input.  The one time we got the noise to stop for a week or so they had messed around with some screws but I don’t recall the specific part name, perhaps it’s what you are referencing.  

Teemok

Kindly, you should be in possession of some documented high and low fire Co2 and Co reading numbers. A replaced gas valve with no documented measurements, pictures of a meter during test, video of ramping high to low, print outs, anything. I don't know if you have the same person, testing with the same meter ,the same way each time. My point is, repeated mistakes give repeat results. If factory instruction haven't been followed exactly and each step or the whole event isn't documented, we are talking about second hand reports. I've followed behind way too many other techs to believe anything they ever just tell a customer. You may have a talented and honest person you are working with. I'm just calling it how I see it from here.

twaasa

I’ve been reading this thread with great interest as I just built a new house with a Triangle Tube Instinct Solo 110 that resonates harmonics (whistling) at low boil too. 

They replaced the gas valve which helped and also did a combustion analysis…at which point they said they needed a new circuit board and “inducer.”  All this because they couldn’t get the readings they needed.

So feeling I too got a lemon is an understatement.   The techs are sure it’s the inducer that is causing the noise and it certainly seems that’s where it’s coming from.  They said they’ve dealt with this problem before.

All of this is covered under warranty but at what point does one just get a new boiler - after every part has been changed out and you slip past the warranty period - definitely a concern of mine.

Kynes1000 - did you ever get it fixed?  And I haven’t heard anyone talk of an inducer as the problem?  I’m basically illiterate when it come to all this but with all these problems I’m learning fast!

twaasa

Also, my next step is to create a sound deadening box with acoustic tiles around the unit… anyone know how much space I need to allow for? 

Teemok

The sound indicates a problem. Damping the sound, may make it more tolerable to you but it fails to solve the problem. The poor guys from TT tech support have been attempting to solve and teach for so long they can come off as curt, unhelpful, indifferent even. It's not fair for them to have to educate all comers but there they are. The problems confronted rarely change much but the installers do. We always suspect it's the product and some times it is but frequently it's something existing unnoticed or something installers have done.
I personally have not seen a control board or a new fan be the cause of harmonic sounds on any boiler. Many times when tuning numbers can't be achieved or they fluctuate it is an external issue like: varying gas volume supply, flue effective length too long or short, flue pipe trapping water, intake air and exhaust pressure differences (wind related), condensate draining problems, etc. There's a lot to get right.
In the early days of exhaust gas analyzers, trusting them was difficult because they weren't great. A few times I'd get numbers that were off. If I tuned to the meter the boiler would operated poorly. If I tuned too rich it would sound better. Forced to tune by sight and sound, I'd leave the equipment running smoothly with readings that were too rich. I'd returned with a known good analyzer to find it close to good. Point is, swapping many parts on the strength of a single meters readings is not advised.

If this procedure is not followed exactly with accurate measuring devices, than it hasn't been done at all.
https://cdn.triangletube.com/wp-content/uploads/2021/12/21205002/EB073-Instinct-Gas-Valve-Adjusment.pdf

GGross

@twaasa

It is a problem most likely associated with either improper venting, improper combustion setup, improper flue attenuator (they ship a foam silencer with that unit, correct one needs to be used on install)

I deal with Triangle Tube it is one of the main lines I deal with. One time I had a customer call with the same issue, they spent days troubleshooting, they just had the vents on backwards, then we dialed in combustion and all was good. Another required a bit more tuning. The older models on LP gas required a specific procedure to be followed during setup that everyone skipped.

It is possible that the boiler required the new board as part of the fix for LP combustion tunings, there was a bad programming on some model boards that we were able to fool in the field until a fix was available. Howling/whistling was not caused by this issue it was separate

twaasa

I greatly appreciate your replies…it gives me more confidence that it’s a technical issue that can eventually be figured out and not a bad boiler.